There are two possibilities for fixing a pipe, particularly a rubber pipe, for example in the wall of a liquid storage reservoir, and obtaining a tight connection. The first one consists in using a member which will be mechanically and rigidly fixed to the wall, for example by screwing, and which will also serve as a pipe connecting endpiece. This first solution requires that the wall be so provided that the fixing operation is carried out in good conditions: tightness is not always perfect.
The second possibility consists in using the rubber pipe as a tightness element in combination with a hollow cylindrical bushing: the bushing is placed inside the pipe, it has a diameter such that the pipe is compressed at the level of the circular orifice, between the rigid wall and the bushing. This second solution is very easy to implement; however, with use, it develops certain disadvantages, due in particular to the diameter of the pipe varying from one manufacture to another; or to diameter irregularities occurring in a pipe during its manufacture. Indeed, for an orifice of set diameter, the fitting is composed of a cylindrical bushing of set external diameter and of a pipe of set internal diameter. Any deviation from these various diameters will entail inaccuracies in the positioning of the fitting which may cause poor tightness or incorrect mounting of the fitting. Another disadvantage resides in the necessity of having a high number of bushing assemblies, or else of having to alter the diameter of the orifice in order to adapt it to the available bushing assembly.